Properties of Ionic Compounds Worksheet
1) Explain why ionic compounds do not conduct electricity in their crystalline form.
2) Why do metals and nonmetals usually form ionic compounds, whereas two bonded
nonmetals are never ionic? Explain.
3) Why is the formation of ionic compounds exothermic?
4) Why do ionic compounds tend to be hard?
5) Describe whether the following compounds are likely to be ionic or not ionic based
on the properties given. Explain your reasoning.
 Compound 1 has a melting point of 545 degrees Celsius and dissolves well in
water.

Compound 2 is is a brittle material that is used to melt road ice during storms.

Compound 3 melts at 85 degrees Celsius and catches fire when heated to 570
degrees Celsius.
© 2009 Cavalcade Publishing
For more chemistry help, visit www.chemfiesta.com.
Properties of Ionic Compounds Worksheet
1) Explain why ionic compounds do not conduct electricity in their crystalline form.
Electricity can only be conducted when ions are moving. In their crystalline
form, the ions in the ionic compound are locked tightly in one place.
2) Why do metals and nonmetals usually form ionic compounds, whereas two bonded
nonmetals are never ionic? Explain.
The difference in electronegativity between metals and nonmetals is high,
meaning that it’s very easy for electronegative nonmetals to take electrons
from non-electronegative nonmetals. If both elements were metals, or if both
were nonmetals, the electronegativities would be too similar for one element
to take electrons from the other.
3) Why is the formation of ionic compounds exothermic?
The interaction of so many positive ions with negative ones gives ionic
compounds considerable stability over their constituent elements. Because
stable = lower in energy, this extra energy is given off as heat during the
formation of ionic compounds.
4) Why do ionic compounds tend to be hard?
The cations and anions are locked tightly into place because of their opposite
charges – as a result, it’s difficult to move the ions and the material is very
hard.
5) Describe whether the following compounds are likely to be ionic or not ionic based
on the properties given. Explain your reasoning.
 Compound 1 has a melting point of 545 degrees Celsius and dissolves well in
water. The high melting point points toward an ionic compound, though the
fact that it dissolves is irrelevant.

Compound 2 is is a brittle material that is used to melt road ice during storms.
This is ionic. The brittleness points toward this, though the road ice thing
doesn’t really give any useful information.

Compound 3 melts at 85 degrees Celsius and catches fire when heated to 570
degrees Celsius. This is a little ambiguous. Ionic compounds tend to have
very high melting points, but in the case of organic solids this isn’t
necessarily true. The catching fire part, however, gives more evidence to
this not being ionic.
© 2009 Cavalcade Publishing
For more chemistry help, visit www.chemfiesta.com.
© 2009 Cavalcade Publishing
For more chemistry help, visit www.chemfiesta.com.